Various compositions are known that function to stabilize organic materials against oxidative, thermal or light-induced degradation. Such stabilization compositions may have broad applications in thermoplastics such as polyolefin, thermoset resins such as polyurethanes, and coating formulations. One problem with polyurethane foams, for example, is that such foams tend to yellow after a certain period of time. Yellowing of foam products is undesirable. Such yellowing may be caused by NOx gas fading or UV radiation.
U.S. Pat. Nos. 4,325,863 and 4,338,244 to Hinsken disclose 3-aryl benzofuran-2-ones and their dimers as new class of stabilizers in various organic polymers such as polyolefins, polyurethanes and polyesters.
U.S. Pat. Nos. 5,367,008 and 5,369,159 and 5,428,162 to Nesvadba disclose the preparation of various 3-(alkoxyphenyl)benzofuran-2-ones and 3-(acyloxyphenyl)benzofuran-2-one derivatives, for use as polymer stabilizers.
The prior art provides a number of relatively non-reactive, solid stabilizers. Solids are difficult to use in manufacturing processes. Solids provide difficulties in handling, migration, fogging, and blooming.
New and more effective stabilizing compounds are needed in the industry. This invention provides such compounds.